1. Field of Application
The present invention relates to a vehicle-use visual field assistance system incorporating an information dispatch apparatus, for providing assistance to the driver of a vehicle by transmitting images to the vehicle showing conditions within regions (blind spots) which are blocked from the field of view of the driver by external objects such as buildings.
2. Description of Related Art
Types of vehicle-use visual field assistance system are known whereby when a vehicle (referred to in the following as the object vehicle) approaches the vicinity of a street intersection where the view ahead of the vehicle is partially obstructed by bodies external to the vehicle, such as buildings located at the right and/or left sides of the intersection, images are transmitted to the object vehicle showing the conditions at the current point in time within a region of the street intersection which is blocked from the driver's view, i.e., a region which is a blind spot with respect to that vehicle.
Such a known type of vehicle-use visual field assistance system includes a camera located near or in the street intersection which is positioned and oriented to capture images of the blind spot, and an optical beacon which is located in a position for communication with the object vehicle. The term “camera” as used herein signifies an electronic type of camera, e.g., having a CCD (charge coupled device) image sensor, from which digital data can be acquired that represent an image captured by the camera. Data expressing successive blind-spot images captured by the street intersection camera are transmitted to the object vehicle via the optical beacon, by an information dispatch apparatus. The object vehicle is equipped with a receiver apparatus for receiving the transmitted blind-spot images, and a display apparatus for displaying the blind-spot images. Such a system is described for example in Japanese patent application publication No. 2003-109199.
With such a known type of vehicle-use visual field assistance system, the images that are displayed by the display apparatus of the object vehicle, showing the conditions within the blind spot, are captured from the viewpoint of the street intersection camera.
The viewpoint of a camera or a vehicle driver is determined by a spatial position (viewpoint position, i.e., determined by ground location and elevation (with the latter being assumed to be the above-ground height, in the following description of the invention), and a viewing direction (i.e., orientation of the lens optical axis, in the case of a camera).
A problem which arises with known types of vehicle-use visual range assistance system such as that described above is that, since the viewpoint of the street intersection camera is substantially different from the viewpoint of the driver of the object vehicle, it is difficult for the driver to directly comprehend the position relationships between the object vehicle and bodies which must be avoided (other vehicles, people, etc.) and which appear in an image that has been captured by the street intersection camera.